The US State Department is reportedly evaluating a video released by the Taliban in Afghanistan that shows a Canadian man and his American wife warning that they will be killed unless their captors’ demands are met.

John Kirby, the US State Department spokesman, made the announcement in a press briefing on Tuesday, saying, the video purportedly showing Canadian Joshua Boyle and American Caitlan Coleman is “being examined for its validity.”

In the video, Boyle, 33, and Coleman, 31, urge Canada and the US to pressure the Afghan government into changing its policy on executing captured Taliban prisoners.

“They will execute us, women and children included, if the policies of the Afghan government are not overturned either by the Afghan government or by Canada somehow, or United States,” Boyle says in the video.

The State Department spokesman said the US government is concerned about the couple’s welfare and urged “their immediate release on humanitarian grounds.”

Boyle and Coleman were captured in 2012 while traveling in a mountainous region near the Afghan capital Kabul.

Afghanistan has been gripped by insecurity since the US and its allies invaded the country as part of Washington’s so-called war on terror. Many parts of the country still remain plagued by militancy despite the presence foreign troops from many US allies.

Taliban have regrouped since the death of former leader Mullah Akhtar Mansour earlier in the year and are reported to be currently in control of more than 65 percent of the war-torn country.